Noctua’s new NF-A Series of fans blends legendary Noctua features, such as AAO Frame with Stepped Inlet Design and Flow Acceleration channels for the utmost in quiet performance, with some new twists and specializations. The NF-A Series 140mm fans come in three very unique models, the NF-A15 PWM, NF-A14 FLX and NF-A14 ULN. The NF-A15 PWM features a rounded 140x150mm frame with 120mm mounting points and 300~1200rpm operation, making it ideal for use on CPU coolers. The NF-A14 pieces use the standard square frame and 140mm mounting, along with 3-pin connections making them more suitable for use in cases and radiators.